The principle of connective tissues in meat fluorescing when exposed to a particular radiation wavelength has been known for some time as described by Swatland, H. J. Objective Measurement of Physical Aspects of Meat Quality, Reciprocal Meat Conference Proceedings, Vol. 42, 1989. Initial investigations in the development of a probe, which is capable of both exciting and collecting fluorescence from connective tissue in meat, are described in Swatland, H. J. Analysis of Signals from a UV Fluorescent Probe for Connective Tissue in Beef Carcasses, Computers and Electronics in Agriculture (6, 1991) 225:234 and Bidirectional Operation of a UV Fluorescent Probe for Beef Carcass Connective Tissues, Computers and Electronics in Agriculture (7, 1992) 285:300, both of Elsevier Science Publishers B. V. Amsterdam. The original probe was an adaptation of a fat depth probe used by the Danish Meat Research Institute in Denmark for measuring the depth of fat on pig carcasses. The probe was adapted by the use of an optical fibre which was inserted in the device. The fibre was cut at an angle so that the interface optics were asymmetrical. Exciting radiation was supplied in the optic fibre from a 100 watt short arc mercury source directed through a heat absorbing filter, a red attenuation filter and a dichroic mirror. Light peaking at 365 nanometers was directed into the proximal end of the optic fibre with a microscopic objective. Fluorescence from the connective tissues in contact with the optical fibre of the probe was measured through the dichroic mirror at the proximal end of the fibre with a flat response silica detector and a radiometer. The dichroic mirror was used as a chromatic beam splitter to separate the outgoing excitation light at 365 nanometer from the incoming fluorescent emission at a wavelength considerably greater than 365 nanometer. A depth measurement device for measuring the depth to which the probe was plunged into the carcass was provided either by an optical shaft encoder to trigger photometer measurements at set increments through the carcass, or a continuously variable analog device, such as a potentiometer. The operation of the potentiometer can be affected by temperature.
The positioning of the glass optic fibre in the probe was also suggested, instead of being cut at an angle, of being slightly bent or rounded in conjunction with a plurality of additional thin fibres as described in the article by Swatland, H. J., Bi-directional Operation of a UV Fluorescence Probe for Beef Carcass Connective Tissues Computers and Electronics in Agriculture 7(1992) 285:300. The use of the multiple fibres around the glass optic fibre was to gather additional information in respect of shape of the connective tissue as the probe passed by the connective tissue.
Extensive analysis of the collected fluorescence from use of the meat probe is described in several papers by Swatland in Food Research International which include Correction for Baseline Drifting in Probe Measurements of Connective in Beef, Food Research International 26, 1993 371:374; An Anomaly in the Effective Temperature on Collagen Fluorescence in Beef, Food Research International, 26, 1993 271:276 and Correlations of Mature Beef Palatability with Optical Probing of Raw Meat, Food Research International, Vol 28, No. 4, pp 403-416, 1995. Swatland also published with others in Swatland et al., An Effective Connective Tissue on the Taste Panel Tenderness for Commercial Prime Beef Detected with a UV Fibre Optic Probe (cite to be inserted) and UV Fibre Optics Probe Measurements of Connective Tissue in Beef Correlated with Taste Panel Scores for chewieness, Food Research International, Vol 28. No. 1, pp 23-30, 1995. Although considerable work has been done in the area of correlating the fluorescent signature of meat when probed with the apparatus to provide an indication of meat tenderness, the widespread use of the technology has been limited by several factors. These include the prohibitive costs and the inconvenience associated with the concept that a large, cumbersome device was necessary to protect delicate electronic components from the harsh environment typically found in a slaughterhouse. In addition, many factors may cause toughness in meat including the distance between fibres, the thickness of the fibre and the type of fibre. For example, Type I and Type III collagen have different fluorescent emission spectra. While the probes described in the prior art were capable of detecting major septa of connective tissue, the distance between the point of data collection and processing in conjunction with the lack of dedicated software resulted in a signal to noise ratio that was insufficient to detect very thin fibres. Thus, little information could be gathered about the relative role of narrow high fluorescence versus a wide septum of low fluorescence nor was it possible to accurately detect the spacing of the peaks (i.e. many small peaks close together). The current invention addresses these problems.